This invention relates to luminous dot sighting instruments and more particularly to such instruments used in connection with a telescope on a firearm as an aid to sighting the firearm on a target.
Optical sighting instruments having a sighting tube have included cross hairs in the tube to define the optical center of the instrument. The user, such as a firearm marksman, looks into the sight and places the cross hairs on the target in the view to aim the firearm. The cross hairs are illuminated by light from the view. At twilight, in haze or fog and at other times when visibility is low, the cross hairs are difficult to see, and at night they cannot be seen at all. One solution to this problem has been the luminous dot sighting instrument.
A luminous dot sighting instrument is used to view a target and is usually attached to a rifle or other firearm to sight the rifle on the target. The luminous dot is generated inside the instrument and is superimposed on the view of the target by a transparent mirror in the instrument. The mirror is transparent to light from the target scene and reflects light from the luminous dot. In this way the luminous dot is superimposed on the target scene as viewed through the instrument and serves the purpose of the cross hairs. Thus, this type of sighting instrument is called a reflex luminous dot sighting instrument. The dot does not depend on light from the view and can be made as bright as desired by the user by controlling the brightness of the luminous dot source.
The instrument is often a sighting tube containing the transparent mirror (window/mirror) and the luminous dot source is a light emitting diode (LED) inside the tube. With the sighting tube are also a battery, brightness control circuit and switch for the LED, usually fixedly attached to the tube. Or the sighting instrument may be a telescope, in which case the LED is inside the telescope and the battery, control circuit and switch are carried on the outside of the telescope as part thereof. In either case, the instrument is attached to a rifle to aid the user in pointing the rifle to hit the target viewed through the instrument.
In such reflex luminous dot sighting instruments, with or without a telescope, the LED is contained in the instrument wherein light is projected from the LED onto a tilted window/mirror that has a mirror coating so that light from the view passing through the lens is joined by light from the diode that reflects from the mirror coating. The user looking into the instrument attached to his rifle sees the target view with the luminous dot at the center and points the rifle to place the dot on the target in the view and fires the rifle. With a properly mounted and adjusted sighting instrument the user can quickly view the target area, put the dot on the target and fire the rifle with great accuracy.
Heretofore, a number of reflex type luminous dot sighting instruments, some with telescopes and some without, have been used with adjustments for range and windage to be made by the firearm user. The adjustments for range and windage are adjustments in elevation angle and azimuth angle, respectively, of the instrument with respect to the firearm and are set by the user using his estimates of range and windage. In all of these, the target view and the luminous dot are combined by the tilted window/mirror or lens/mirror with a mirror coating and light from the target view passes through the tilted lens while light from the LED that forms the luminous dot reflects from the lens mirror coating. Also, in all of these, the LED is contained within the sighting tube or telescope and is powered by a battery in circuit with the LED and a brightness control and/or switch are all attached to and carried by the tube or telescope. Thus, each sighting tube or telescope comes equipped with the LED, battery and brightness control and/or switch.
Where a telescope is included, the light from the LED is focused by the tilted lens/mirror on the same image plane as the target view so that the user sees the target view and the luminous dot all in focus at the same plane with the luminous dot precisely at the center of the target view. The LED is enclosed within the telescope and the dot appears to the user the same size, shape and color for all target views, at the center of the target view, whether the target is far or near (long or short range elevation) and whether there is any adjustment for windage, left or right.
Such a luminous dot sighting instrument including a telescope is described in: my U.S. Pat. No. 5,205,044, issued Apr. 27, 1993, entitled Luminous Dot Sighting Instrument; and in my co-pending U.S. patent applications Ser. No. 07/981,012, filed Nov. 24, 1992, entitled: Reflex Luminous Dot Sighting Instrument With Undesired Dot Light Blocking; and Serial Number (unknown), filed Nov. 19, 1993, entitled Reflex Luminous Dot Sighting Instrument With Dot Light Aperture.
Elevation and windage adjustment controls are provided on all embodiments described in my above mentioned U.S. Patent and co-pending U.S. Patent Applications. In some, the adjustment requires a tool like a screwdriver and in others that have a thumb wheel projecting from the instrument and do not require a tool, the thumb wheel turns a screw that pushes against the sighting tube on a spring mount so that: adjustment in one direction is accomplished by turning the wheel clockwise to push against the tube; and adjustment in the opposite direction is accomplished by turning the wheel counterclockwise, allowing the spring mount to move the tube in the opposite direction. Thus, the control is not so connected to the tube that it can push and pull the tube; it can only push the tube and depends on the spring for adjustment in the opposite direction.
In all of these embodiments the elevation and windage adjustment controls are located for right hand use while the user is sighting the rifle and left hand use is awkward.
Heretofore, where elevation and windage adjustment controls have been provided having push and pull connection to the sighting tube, and so do not depend on a spring return force, the pushing and pulling has been done by a rigid connection to the tube, which does not allow the end of the tube that is pushed/pulled by the control to move along an arcuate path; it can only move along a straight path. This can cause the control to bind unless the angle of elevation or windage adjustment is very small and the control parts fit loosely.